Everything you need to know about leaky gut

In this first instalment in the A No Grainer gut health series we look at why the gut is such an important organ and all about a condition known as ‘leaky gut.’

What is the gut?

When we think of our guts most of us probably picture our intestines, hopefully not sprawling out of our body like in a horror film. In fact our gut is a hollow tube that passes from mouth to anus, often referred to as the gastrointestinal tract. This system is responsible for our entire digestive process, ensuring the food we eat is turned into calories and nutrients that nourish our body. Critically, when the gut is working properly it acts as a barrier to prevent the foreign specimens (food) that we put into our bodies from getting into our bloodstream. It is able to carefully select and absorb the calories, minerals and vitamins that we need and send them to our cells for energy.

Additionally around 75% of our immune system is located in our gut, so for healthy resistance to disease and other ailments gut health is essential. For the purposes of this article we will focus on the small and large (colon) intestines.

There are two important variables that influence the health of our gut and hence the rest of our body: 1) the lining of the gut; and 2) the microorganisms that populate it, the microbiota. Sometimes the environment created by the microorganisms in our gut is referred to as our microbiome. Gut related issues and many resulting conditions are caused when the lining is compromised (leaky gut) or when our gut microbes become unbalanced.

The lining of the gut

The intestinal wall or the lining of the gut is made up of millions of epithelial cells, which are cells found on membranous tissues and separated by tiny intercellular substances. (1) The intestinal wall cells form a barrier between the inside of your gut and your bloodstream. The fact that the lining is made up of millions of cells means that the gut walls are slightly permeable and this how we absorb the bulk of our nutrition from the food we eat. However, the permeable nature of the digestive tract also means that it is highly sensitive and there are a number of foods that can cause damage to the lining leading to a condition now widely known as ‘leaky gut.’

Leaky gut

Leaky gut or intestinal permeability is when the usually tight junctions (the microvilli) between the cells in the gut wall become loose or damaged. This allows protein molecules that should be kept inside the gut to enter the bloodstream, which in turn can trigger the body’s inflammatory response. When the body thinks it is under threat from foreign invaders, such as protein molecules that have slipped through the gut, then it mounts an immune response. If this is a prolonged occurrence then your body can lose its ability to discern what is actually a foreign specimen is and what is part of your own body. This is where autoimmune conditions can develop, because your body might start attacking itself. There are an increasing number of studies that point to leaky gut as a precipitating factor in Type 1 Diabetes, Multiple Sclerosis, Hashimotos and many others.

According to Alessio Fasano, a leading paediatric gastroenterologist and researcher in Coeliac disease, all autoimmune conditions have three factors: a genetic susceptibility, antigen exposure, and increased intestinal permeability.

In a 2012 journal article he wrote that many autoimmune conditions…

“…are characterized by increased intestinal permeability secondary to non-competent tight junctions that allow the passage of antigens from the intestinal flora, challenging the immune system to produce an immune response that can target any organ or tissue in genetically predisposed individuals…”

I talk more about proteins that can cause leaky gut and the link to autoimmunity in this post on grains. The important thing to note is that a damage lining of the gut can have very severe consequences that manifest in different ways from skin conditions to mood disorders. This damage can be caused by eating foods that you are intolerant to (such as gluten or diary) and other ways that I will discuss in part IV of this series.

In the part II of this series I will focus more on the microbiome and the impact of gut bacteria.